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Fig. 1. Time-window of requirement for Nodal activity in mesendoderm induction. (A) Xenopus embryos were subjected to 200 μM SB-505124 (SB) or injected with 5 ng Lefty recombinant protein at the indicated stage (st.), and analysed by WISH at early gastrula stage. Control embryos were treated with DMSO. In this and the following figures, the number of embryos exemplified by the photograph over the total number of embryos analysed is indicated. For sox17α, Xbra and goosecoid, embryos were bisected prior to WISH and are viewed dorsal to the right, animal to the top. For foxI1e, views are animal, with dorsal to the top. (B) Q-PCR analysis was performed on the same embryos as in A. (C) Western blotting was performed on the same embryos as in A. The bar charts present the ratio of pSmad2 to α-tubulin levels, with respect to controls (DMSO and MOCK), which were set to 1. |
